Creep-induced heterogeneous precipitation of Laves phase with two morphologies in tempered martensite ferritic steels

Abstract

We report two typical morphologies (elongated- and blocky-shaped) of the Laves phase in tempered martensite ferritic steels during creep process, originating from the two independent formation paths, i.e. along grain boundaries (GBs) and neighboring M₂₃C₆. This is attributed to the multi-element segregation (Cr, Mn, Si and W) at GBs and adjacent M₂₃C₆ that serves as suppliers of Laves phase formers. Furthermore, the subsequent different growth mechanisms play crucial roles in the two typical morphologies. Our findings improve the understanding of Laves phase heterogeneous precipitation and provide new insights for the innovation of novel heat-resistant steels with superior creep strength.

GRAPHICAL ABSTRACT

KEYWORDS:

• Tempered martensite ferritic steels
• creep deformation
• Laves phase
• heterogeneous precipitation
• precipitation mechanism

Disclosure statement

No potential conflict of interest was reported by the author(s).

Statement of novelty

We have demonstrated the creep-induced heterogeneous precipitation mechanisms of Laves phase in tempered martensitic ferritic steels through a combination of high-resolution characterization techniques and interrupted creep tests.

Additional information

Funding

This research was financially supported by the National Natural Science Foundation of China (Grant number 51975405 and 52025052).